On 2021.03.26 01:09:53 +0800, Fred Gao wrote:
> Before opregion version 2.0 VBT data is stored in opregion mailbox #4,
> but when VBT data exceeds 6KB size and cannot be within mailbox #4
> then from opregion v2.0+, Extended VBT region, next to opregion is
> used to hold the VBT data, so the total size will be opregion size plus
> extended VBT region size.
>
> Since opregion v2.0 with physical host VBT address would not be
> practically available for end user and guest can not directly access
> host physical address, so it is not supported.
>
> Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> Signed-off-by: Swee Yee Fonn <swee.yee.fonn@xxxxxxxxx>
> Signed-off-by: Fred Gao <fred.gao@xxxxxxxxx>
> ---
Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Hi, Alex, pls let us know if you have other concern to merge this one.
Thanks!
> drivers/vfio/pci/vfio_pci_igd.c | 53 +++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/vfio/pci/vfio_pci_igd.c b/drivers/vfio/pci/vfio_pci_igd.c
> index e66dfb0178ed..228df565e9bc 100644
> --- a/drivers/vfio/pci/vfio_pci_igd.c
> +++ b/drivers/vfio/pci/vfio_pci_igd.c
> @@ -21,6 +21,10 @@
> #define OPREGION_SIZE (8 * 1024)
> #define OPREGION_PCI_ADDR 0xfc
>
> +#define OPREGION_RVDA 0x3ba
> +#define OPREGION_RVDS 0x3c2
> +#define OPREGION_VERSION 0x16
> +
> static size_t vfio_pci_igd_rw(struct vfio_pci_device *vdev, char __user *buf,
> size_t count, loff_t *ppos, bool iswrite)
> {
> @@ -58,6 +62,7 @@ static int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)
> u32 addr, size;
> void *base;
> int ret;
> + u16 version;
>
> ret = pci_read_config_dword(vdev->pdev, OPREGION_PCI_ADDR, &addr);
> if (ret)
> @@ -83,6 +88,54 @@ static int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)
>
> size *= 1024; /* In KB */
>
> + /*
> + * Support opregion v2.1+
> + * When VBT data exceeds 6KB size and cannot be within mailbox #4, then
> + * the Extended VBT region next to opregion is used to hold the VBT data.
> + * RVDA (Relative Address of VBT Data from Opregion Base) and RVDS
> + * (Raw VBT Data Size) from opregion structure member are used to hold the
> + * address from region base and size of VBT data. RVDA/RVDS are not
> + * defined before opregion 2.0.
> + *
> + * opregion 2.1+: RVDA is unsigned, relative offset from
> + * opregion base, and should point to the end of opregion.
> + * otherwise, exposing to userspace to allow read access to everything between
> + * the OpRegion and VBT is not safe.
> + * RVDS is defined as size in bytes.
> + *
> + * opregion 2.0: rvda is the physical VBT address.
> + * Since rvda is HPA it cannot be directly used in guest.
> + * And it should not be practically available for end user,so it is not supported.
> + */
> + version = le16_to_cpu(*(__le16 *)(base + OPREGION_VERSION));
> + if (version >= 0x0200) {
> + u64 rvda;
> + u32 rvds;
> +
> + rvda = le64_to_cpu(*(__le64 *)(base + OPREGION_RVDA));
> + rvds = le32_to_cpu(*(__le32 *)(base + OPREGION_RVDS));
> + if (rvda && rvds) {
> + /* no support for opregion v2.0 with physical VBT address */
> + if (version == 0x0200) {
> + memunmap(base);
> + pci_err(vdev->pdev,
> + "IGD assignment does not support opregion v2.0 with an extended VBT region\n");
> + return -EINVAL;
> + }
> +
> + if (rvda != size) {
> + memunmap(base);
> + pci_err(vdev->pdev,
> + "Extended VBT does not follow opregion on version 0x%04x\n",
> + version);
> + return -EINVAL;
> + }
> +
> + /* region size for opregion v2.0+: opregion and VBT size. */
> + size += rvds;
> + }
> + }
> +
> if (size != OPREGION_SIZE) {
> memunmap(base);
> base = memremap(addr, size, MEMREMAP_WB);
> --
> 2.24.1.1.gb6d4d82bd5
>
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